A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
1. Field of the Invention
The present invention is directed to computer systems, and more particularly, to a system for remote emulation of a computer system console.
2. Description of the Prior Art
Large computer systems, including mainframes and enterprise servers, have traditionally included a primary console to enable system administrators to configure and administer the computer system. These primary consoles typically take the form of a monitor, keyboard, and often a pointing device, such as a mouse, attached locally to the computer system. In some cases, the primary console comprise a small workstation that is tightly coupled to the larger computer system.
In order to provide additional flexibility and ease of administration of a large computer system, remote consoles have been provided that emulate the primary console of the computer system on a remote workstation over a modem or network connection. Typically, video information representing the screen of the primary console is captured and transmitted over the network to the remote workstation, which uses the information to reproduce the screen of the primary console on the remote workstation. Keystroke and mouse input at the remote workstation is transmitted to the host computer system and inserted into the system keyboard controller. A system administrator is thus able to administer and configure the computer system from the remote location as if using the primary console of the computer system.
Unfortunately, prior art remote console emulators suffer from a number of drawbacks. Prior art remote console emulators typically must access the host computer system bus to obtain video information to transmit to the remote console. Such an impact on the system bus of the host computer will have an effect on its performance. Prior art remote console emulators also often require special software, such as drivers and the like, running on the host computer. These too can impact the performance of the host computer. Another disadvantage of many prior art remote console emulators is that they do not work equally well in both text and graphics modes, mainly as a result of the software complexities of those solutions. Consequently, there is a need for an improved remote console emulation system that overcomes these noted deficiencies of the prior art. The present invention satisfies this need.
The present invention is directed to a system, and an adapter card thereof, for providing, via a network, emulation of a console of a first computer system on a second, remotely located computer system on the network. The system comprises the adapter card, which is installed in the first computer system, and a client program executing on the remotely located computer system. According to the present invention, the adapter card comprises a local bus that interfaces to an input/output bus of the first computer system when the adapter card is connected to the first computer system, a graphics controller coupled to the local bus that interacts with the first computer system to generate a representation of a console screen of the first computer system, a network interface controller coupled to the local bus that provides a connection to the network, and a processor coupled to the local bus that determines changes in the representation of the console screen of the first computer system and that transmits information about the changes to the remotely located computer system via the network interface controller. Because the graphics controller, processor, and network interface controller are all co-located on the adapter card, communication among them over the local bus does not impact the performance of the input/output bus of the first computer system. Moreover, the system of the present invention does not require any special software executing on the host computer system.
The client program executes on the remote computer system. It receives the information transmitted from the adapter card and reproduces therefrom the representation of the console screen of the first computer screen on a display device of the remote computer system.
According to another aspect of the present invention, the adapter card further comprises a peripheral device interface coupled to the local bus that can be controlled selectively by either the first computer system or the processor. Selection of either the processor or the first computer system to control the peripheral device interface is achieved by setting/resetting a flag variable stored on the adapter card. When the computer system is started, the processor on the adapter card examines the flag to determine whether it should take control of the peripheral device interface or whether the first computer system should take control. If the processor is to take control, the processor causes a modified BIOS for the peripheral device interface to be loaded by the first computer system that halts the first computer system in order to allow the processor to take control of the peripheral device interface.
Additional features and advantages of the present invention will become evident hereinafter.